1. Field of the Invention
The present invention relates generally to models of the human knee joint, and more particularly, to a method of providing a human knee model suitable for teaching arthroscopic surgical technique.
2. Description of the Prior Art
Arthroscopy was initially developed in Japan approximately 40 years ago. However, only recently has arthroscopic surgery become widely recognized as being vastly superior to traditional methods of surgery involving joints of the human body, particularly the knee joint. Arthroscopic knee surgery is typically performed through three small one-quarter inch incisions while the patient is under general anesthesia. A fiber optic telescope or arthroscope, smaller than the size of a pencil, is inserted into the knee for allowing the surgeon to thoroughly examine all parts of the knee joint. A small television camera may be attached to the arthroscope, and the magnified image of the inside of the knee joint is displayed on a television screen. After the injury to the knee joint has been defined precisely, small delicate instruments are inserted through one of the other small incisions, and the damaged portion of the knee joint is repaired or corrected. The small incisions avoid the large scars of a conventional open surgical operation and shorten the patient's recovery time while reducing postoperative pain.
Operative arthroscopy of the knee demands that the surgeon learn new psychomotor skills. The surgeon must be able to manipulate the arthroscope, inserted within a first small incision, for locating the area of the knee joint to be viewed while simultaneously manipulating a delicate instrument, inserted within a second small incision, in order to direct the tip of the instrument toward the highly magnified area of the knee viewed by the arthroscope. Thus, the surgeon must develop new eye-brain and eye-hand stereotaxis to successfully perform operative arthroscopy.
Resident surgeons usually learn surgical technique within the operating room through observation of a highly skilled surgeon. Unfortunately, this traditional method of training through observation does not lend itself to learning and developing the psychomotor skills required for arthroscopic surgery. In view of the relatively large number of surgeons expressing an interest in learning arthroscopic surgical technique, individualized training of interested surgeons by practicing orthopedists skilled in arthroscopic surgery is not practical.
A practical and preferred method of teaching and learning the required psychomotor skills is to provide a "hands-on" workshop wherein each student actually manipulates the arthroscope and the related instruments. However, a workshop approach toward learning operative arthroscopy of the knee requires a specimen into which the arthroscope and various operating instruments may be inserted. Actual human knee specimens obtained through amputations and the like are difficult to obtain in quantity for obvious reasons. Artificial knee models are available but are relatively expensive. In addition, such artificial knee models have not proven satisfactory for teaching arthroscopic surgical technique because they do not provide a realistic arthroscopic appearance, a realistic tactile sensation, or allow for continuous irrigation of the knee joint as would be utilized during actual surgery.
Accordingly, it is an object of the present invention to provide a model of the human knee that can be provided in large quantities for relatively little cost.
Another object of the present invention is to provide a model of the human knee that may be utilized to learn and develop the psychomotor skills required to perform arthroscopic surgery of the knee.
A further object of the present invention is to provide a model of a human knee into which an arthroscope may be inserted, the model providing a realistic arthroscopic appearance, realistic tactile sensation, and allowing for continuous irrigation of the knee joint.
The present inventor initially developed a human knee model which achieved the above stated objects of the present invention through a method of modifying a natural bovine knee and surrounding the modified bovine knee with a synethetic, flexible fluid impervious covering for allowing continuous irrigation of the knee joint. Through continued useage of and experimentation with the knee model initially developed, the present inventor has determined that, while the initial knee model is well suited for teaching arthroscopic surgical techniques, the natural cartilage, ligaments and other various tissues within the modified bovine knee joint are eventually cut away and destroyed following repeated uses of the knee model. Similarly, the synthetic covering surrounding the knee joint is typically punctured several times during each arthroscopic surgery training session and ultimately lacks sufficient integrity to irrigate the knee joint after the model has been used a number of times.
Of course, when a particular knee model has been used a number of times and has been depleted in the manner described above, it may simply be discarded in favor of a fresh, new knee model. However, the training facility or other user of the knee model must then store a number of replacement models, preferably in frozen storage to prevent decomposition of the knee joint. As the knee models are somewhat bulky due primarily to the portions of the bovine femur and tibia bones extending from the knee joint, a relatively large volume of frozen storage may be required to store an adequate supply of knee models. Furthermore, the shipping and packaging costs associated with such a relatively bulky knee model may become disadvantageously appreciable, particularly if such knee models are shipped by the manufacturer under refrigeration.
Furthermore, the knee model originally developed by the present inventor lacked an integral patella. The bovine knee joint includes a patella which is much larger than a human patella and which obstructs arthroscopic viewing of the interior of the knee joint. Thus, the quadriceps tendon was severed within the knee model originally developed by the present inventor for allowing the bovine patella to be removed to facilitate access of the arthroscope and surgical instruments within the interior of the knee joint. However, the lack of an integral patella in front of the knee joint lessens the ability of the knee model to accurately simulate the appearance of a human knee.
In addition, bovine knees supplied by meat packing houses are typically devoid of any muscle or other soft tissue around the femur or tibia bones. Consequently, attachment of the synthetic, flexible fluid-impervious covering over the knee joint results in the upper and lower ends of the covering being sealed directly against the femur and tibia bones, respectively. The external appearance of the covering surrounding the knee model consequently has a form which does not closely correspond to that of the skin surrounding a human knee.
Accordingly, it is an object of the present invention to provide a model of the human knee that may be utilized to learn and develop the psychomotor skills required to perform arthroscopic surgery of the knee and wherein the model may be easily and inexpensively renovated to its original condition following a series of repeated useages.
It is a further object of the present invention to provide such a human knee model providing a more realistic appearance by including a human-like patella and a more human-like external form.
These and other objects of the present invention will become apparent to those skilled in the art as the description thereof proceeds.